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Kårekull, O. & Hellgren, H. (2017). Noise and indoor air quality: HVAC noise characteristics.
Open this publication in new window or tab >>Noise and indoor air quality: HVAC noise characteristics
2017 (English)Report (Other academic)
Abstract [en]

Noise from Heating Ventilation and Air Conditioning (HVAC) systems in residential buildings have an influence on the residents´ well-being. The characteristics of HVAC noise have been investigated as to recommend typical spectra for the design of a listening test using sound recordings. An HVAC system layout is developed to represent a system in a residential building where variations of the noise spectrum are possible without the use of unrealistic conditions. From a spectrum shape perspective the main parameter of the system is the balance between noise originated from the heat recovery unit and the duct component related noise. The receiving room spectrum is here mainly modified by the use of different silencers close to the heat recovery unit and the balance between the pressure loss of the air terminal device and a nearby damper. Modifications of the heat recovery unit total airflow and the inflow properties to the air terminal device are also investigated. Variations at both low and high frequencies are possible, at a constant total A-weighted sound pressure level, using these system properties.

Abstract [sv]

Buller från ventilationssystem (HVAC) i bostadshus har en inverkan på de boendes välbefinnande. Ventilationssystemets olika bulleralstrande komponenter har här undersökts för att rekommendera typiska bullerspektra för användning vid ett lyssningstest. Ett ventilationssystem har dimensionerats för att representera ett typiskt system i ett bostadshus där variationer av bullerspektra är möjligt utan att använda orealistiska inställningar. Ljudinspelningar kommer vid ett senare skede genomföras för detta system. Ventilationssystemets luftflöden har definierats utifrån en analys av föreskrivna krav på luftomsättning och genomsnittliga bostadsytor. Riktvärdet för mottagarrummets ljudtrycksnivå är bestämt utifrån befintlig kravställning för ett typiskt vardagsrum. Även efterklangstiden i mottagarrummet är vald utifrån ljudabsorptionen i ett vardagsrum.

Huvudparametern för bullervariationerna är balansen mellan ljud orsakat av ventilationsaggregat i jämförelse med ljud alstrat av kanalkomponenter. Mottagarrummets bullerspektrum har huvudsakligen varierats genom användning av olika aggregatljuddämpare samt modifiering av balansen mellan tilluftsdonets tryckfall och tryckfallet över ett närliggande spjäll. Variationen av tilluftsdonets tryckfall kan ses som ett resultat av lämpligheten i ventilationssystemets injustering och valet av ljuddämpare kan ses som en följd av den akustiska planeringen. Variationer av aggregatets totala luftflöde och egenskaperna hos tilluftsdonets inflöde undersöks också. Det totala luftflödet är en följd av storleken och antalet hushåll som ventilationsaggregatet försörjer. Inströmningsegenskaperna påverkas av tillgängligt utrymme mellan de olika kanalkomponenterna såsom om det finns en böj innan tilluftsdon. Variationer av både låga och höga frekvenser vid en konstant A-vägd ljudtrycksnivå är möjliga med hjälp av de beskrivna systemegenskaperna.

Series
SP Rapport, ISSN 0284-5172 ; 2017:15
Keywords
HCAV, ventilation, residential buildings, flow generated noise
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:ri:diva-29156 (URN)
Projects
Ljud och luft i innemiljön - avvägningar för boendes välbefinnande (E2B2)
Funder
Swedish Energy Agency
Available from: 2017-03-29 Created: 2017-03-29 Last updated: 2018-08-16Bibliographically approved
Gustafsson, O., Teuillieres, C., Hellgren, H., Axell, M. & Dalenbäck, J.-O. (2016). Reversing air-source heat pumps - Noise at defrost initiation and a noise reducing strategy. International journal of refrigeration, 62, 137-144
Open this publication in new window or tab >>Reversing air-source heat pumps - Noise at defrost initiation and a noise reducing strategy
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2016 (English)In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 62, p. 137-144Article in journal (Refereed) Published
Abstract [en]

With the increasing use of air source heat pumps, noise disturbance can be a barrier for further market growth and acceptance. Both steady state noise level and noise events influence reported noise disturbance. In this study one of the transient noise events was investigated: the noise initiated when the heat pump shifts to defrost mode. The results show that noise from a heat pump at defrost initiation was strongly dependent on the pressure differences in the system at the time of the shift. A reduced pressure difference resulted in a lower noise level. A control strategy that adds an idling time for the heat pump just before the shift of the 4-way valve is therefore suggested. This will have a small negative effect (<3%) on the heat capacity of the heat pump but the effect upon the COP will be negligible.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Heat pump, Noise reduction, Pressure differences, Defrost, 4-way valve, Energy, COP
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-417 (URN)10.1016/j.ijrefrig.2015.10.017 (DOI)2-s2.0-84955457991 (Scopus ID)
Available from: 2016-06-23 Created: 2016-06-23 Last updated: 2019-06-18Bibliographically approved
Gustafsson, O., Hellgren, H., Haglund Stignor, C., Axell, M., Larsson, K. & Teuillieres, C. (2014). Flat tube heat exchangers – direct and indirect noise levels in heat pump applications (ed.). Applied Thermal Engineering, 66(5), 104-112
Open this publication in new window or tab >>Flat tube heat exchangers – direct and indirect noise levels in heat pump applications
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2014 (English)In: Applied Thermal Engineering, Vol. 66, no 5, p. 104-112Article in journal (Refereed) Published
Abstract [en]

In the outdoor unit of an air-source heat pump the fan is a major noise source. The noise level from the fan is dependent on its state of operation: high air-flow and high pressure drop often result in higher noise levels. In addition, an evaporator that obstructs an air flow is a noise source in itself, something that may contribute to the total noise level. To be able to reduce the noise level, heat exchanger designs other than the common finned round tubes were investigated in this study. Three types of heat exchanger were evaluated to detect differences in noiselevel and air-side heat transfer performance at varying air flow. The measured sound power level from all the heat exchangers was low in comparison to the fan sound power level (directeffect). However, the heat exchanger design was shown to have an important influence on the sound power level from the fan (indirect effect). One of the heat exchangers with flat tubes was found to have the lowest sound power level, both direct and indirect, and also the highest heat transfer rate. This type of flat tube heat exchanger has the potential to reduce the overall noise level of a heat pump while maintaining heat transfer efficiency.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6617 (URN)10.1016/j.applthermaleng.2014.02.002 (DOI)2-s2.0-84898909466 (Scopus ID)16421 (Local ID)16421 (Archive number)16421 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-09Bibliographically approved
Gustafsson, O., Axell, M., Larsson, K., Hellgren, H. & Teuillieres, C. (2013). Outdoor units of air-source heat pumps - a noise investigation (ed.). In: : . Paper presented at Proceedings of CLIMA 2013.
Open this publication in new window or tab >>Outdoor units of air-source heat pumps - a noise investigation
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2013 (English)Conference paper, Published paper (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12266 (URN)15270 (Local ID)15270 (Archive number)15270 (OAI)
Conference
Proceedings of CLIMA 2013
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-22Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2673-0688

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